content of the article:
blight or brown rot of potato - a very common disease of Solanaceae, to a lesser extent affecting strawberries, buckwheat, castor-oil plant. Name - translation from 2 Greek words: "plant" "destroy."In Russia, the loss of potatoes from the disease - ≈ 4 million tons per year.
The causative agent is not entirely true of mushrooms( different classification systems - different data).In any case, the drugs for treatment are called fungicides, which means "killing mushrooms."Potatoes are infected with zoospores located in the ground, in storage, on post-harvest residues and unselected tubers. Infection of tubers can go( as often happens) from infected foliage: when it rains with water or when it comes into contact with potatoes when harvested. In rainy and warm weather, the disease spreads quickly and can hit the entire field.
Read our article: Potato Diseases with Photos and Description.
Characteristic symptoms of potato disease with late blight
Potatoes planted and the first beautiful green shoots have appeared. Plants are gradually gaining strength. Shrubs become large sprawling. To be a good harvest, but one day you suddenly notice that your potato beds have changed, the bushes are no longer so attractive. Symptoms of the disease are darkening on the parts of plants, later on the spots grow, in the tubers - the mycelium develops deep into. Secondary infection is often settled on the affected organs and completes the destruction of the crop, turning the potato into a putrefactive mass. In wet weather, a pale deposit of a fruiting mycelium develops from the bottom of the leaf.
Herbal flowers on potatoes, the photo shows the defeat of various parts of the plant. The fight against the disease must begin at the first sign, and preferably before their occurrence. Only in this case can you save the harvest and avoid mass destruction.
Facts from the history of
Late blight caused a great famine in Ireland in the years 1845-1849.In just a few years, the country's population fell by a quarter. .. To escape, people tried to emigrate. On ships that had previously served to transport slaves, weakened by hunger and disease, people floated to America. Mortality on ships reached 20-30%. .. These well-developed vessels called this: "coffin-ships" - coffins, literally - the coffin-ship. .. Songs, monuments, people still remember the "Great Potato Hunger". ..
Control measures and prevention of the disease
In suitable weather, the disease develops very quickly, so first of all pay attention to the prevention of the disease. 
- Healthy planting material. Warm up well before planting a week for two selected material and revise it again, removing tubers with the smallest signs of disease.
- Selection of resistant varieties. Absolutely stable does not exist, and yet the difference in susceptibility of various varieties is significant.
- Removal of post-harvest residues. These are the source of infection. Mowing the tops before digging and removing it from the field helps: with infected leaves, there may well be uninfected tubers. Until they meet with diseased tops.
- Maintaining crop rotation. Considering that the pathogen, as written above, develops on other solanaceous birds( still on buckwheat, castor-bean and strawberries, but less on them), therefore planting potatoes after tomatoes or eggplant is a bad idea. Crop rotation is one of the important measures in the prevention of various plant diseases.
- Early Cleaning. With keeping tubers for some time in a dry place for ripening. It helps, especially in rainy, conducive to the development of the fungus weather.
- Avoid overly thickened landings. In such cases, the disease develops faster.
- Hilling. In addition to normal goals, this technique also protects the tubers from infection.
- Choosing a landing site. Humidity is higher in lower areas, moisture often stagnates, which phytophthora needs.
- Don't overdo liming! Favorable disease. ..
- Spatial isolation. As different potato fields, and fields of other plants of the family of solanaceous - tomato, eggplant, because phytophthora affects them as well.
- We adhere to agrotechnics. Plants, as well as people: they are easier to infect and more weakly weakened by poor conditions of development.
- Wisely use top dressing. The introduction of nitrogen drives the tops and often increases the yield, but increases the incidence. But the introduction of potassium or micronutrients, in particular copper - on the contrary, protects the plants.
We begin the first treatments before signs of the disease appear!
This is especially important if the weather is rainy and foggy. The appearance of edible mushrooms in the forests is very approximate, but still a sign: it's time to start processing. And spray periodically, once every two weeks or a decade. How to process potatoes from phytophthora? Any fungicides, the choice is yours - in the store, at companies or in the bazaar range is huge, we buy and make according to the instructions. But people use other means of phytophthora on potatoes, they treat not only fungicides. The result is controversial, there are many fans of different methods, but to fully trust. .. beware. On the other hand, what if it helps? So, sprayed.
- Milk, skimmed or whey( diluted).
- Tincture of garlic.
- Trihopol( buy at the pharmacy) tablet / liter of water.
- Iodine( we buy there).However, it is usually combined, when spraying with milk, 10-15 drops / liter of iodine are added.
- Tincture on superphosphate.
- A weak solution of copper sulfate.
